The invention disclosed herein relates generally to mechanical couplers for rotatable shafts, and more particularly to such couplers of a design which can be simply formed of inexpensive sheet material in a configuration which tolerates shaft misalignment and permits limited overtravel of one shaft relative to another.
Coupler devices of wide variety of designs for generally aligned rotatable shafts are well known. These designs range from simple solid couplers which rigidly connect one shaft to another end to end, to couplers employing a variety of resilient elements for permitting limited relative motion and/or misalignment between the coupled shafts.
One common resilient coupler design type employs a pair of flanges or hubs rigidly fixed to adjacent ends of the shafts, the flanges or hubs being connected to one another through elastomeric material, springs or a functional equivalent. In such an arrangement, the coupler is normally formed of a plurality of parts, some of which may be most advantageously formed by machining or casting. The number and form of the component parts results in a coupler which is relatively complex and expensive.
It is known to simplify this arrangement by appropriately configuring the spring and ends of the shafts so as to eliminate the flanges or hubs. A particular implementation may effectively involve a cylindrical coil spring aligned with the axis of the shafts and connected at opposite ends thereof to the separate shafts. However, the obvious ways of connecting the spring to the shafts in such an implementation either require special forming which may be disadvantageous for production, or are difficult to assemble and disassemble, or do not provide reliable attachment which is adequately free of backlash, or have some other associated disadvantage.
Although existing rotary coupler designs are satisfactory for many applications, a continuing need exists for simpler, less expensive couplers which are adaptable to a variety of applications, and exhibit characteristics such as freedom from backlash, tolerance of shaft misalignment and overtravel of one shaft relative to the other, accommodation of shafts of unequal sizes, simple single piece construction capable of inexpensive and easy manufacture, etc.